The Geoprobe® DT21 Groundwater Profiler is three tools in one! The DT21 Groundwater Profiler allows you to retrieve soil samples, collect groundwater samples, and perform slug testing... at multiple depth intervals... in one probe push. This lets you conduct detailed vertical profiles of groundwater contaminants with ease, or determine vertical and lateral variations in hydraulic conductivity to define preferential contaminant flow paths and optimize remedial system design. The screen interval may be developed with the tubing check valve, and samples can be collected with the pneumatic bladder pump. The screen system of the DT21 profiler is excellent for hydraulic conductivity (slug) testing. The DT21 profiler is also great for sampling at multiple depths and at deeper depths.

This groundwater sampling system is designed around the DT22 Dual Tube Sampling System. This system may be used to conduct soil sampling, groundwater sampling, and slug testing at multiple depth intervals in one probe hole. The dual tube rods are advanced to depth either by soil sampling or with the solid drive point installed. The inner (1.0 inch) rods and solid drive point (or soil sample) are removed so the screen may be installed. Extension rods equipped with an insert tool are used to lower and hold the screen in position at the base of the cutting shoe. The rod grip handle is then used to retract the outer (2.25 inch) rods as the screen is held in position with the extension rods. As the rods are retracted, the 0.75 in. Schedule 40 x 12 in. long, 10-slot PVC screen is exposed to the formation. The screen head seats against the reduced ID of the cutting shoe and O-rings provide a seal. The screen interval may be developed with the tubing check valve and samples can be collected with a bladder pump if desired. Slug test have been sucessfully performed with this system in formation with hydraulic conductivity over 750 ft/day. An adapter is available to isolate the screen from the ID of the 2.25 in. rods with 0.5 inch PVC riser pipe. This option is useful for collecting high-integrity samples or conducting slug tests in lower hydraulic conductivity formations. Bottom-up tremie grouting should be conducted after profiling is completed (screen removed) with an acceptable grout mixture.

DT21 Groundwater Profiler Advantages:

• Conduct detailed vertical profiles of groundwater contaminants with ease.
• Determine vertical and lateral variation in hydraulic conductivity to define preferential contaminant flow paths and optimize remedial system design.
• Specially designed installation and retrieval tools make for quick and easy installation and removal of PVC screen.
• Allows for groundwater sampling between collection of soil samples in amenable conditions (control of flowing sands is necessary in saturated noncohesive formations).
• Adapter allows for connection of 0.5 in. PVC riser directly to the screen to isolate sampling from large rod diameter: minimizes purge volume.
• Use of 0.5 in. PVC riser allows for sample collection without contact with steel rods.
• Slug tests may be conducted through the larger ID of 2.25 in. rods for fast formations, or through 0.5 in. PVC for slow formations.
• Slug tests easily conducted with Pneumatic Slug Test Kit from Geoprobe Systems®.
• Low cost PVC parts minimize expense of groundwater sampling.
• Operates with the same tools you use everyday for DT22 Dual Tube soil sampling.